Tire Deflectors/Spats

[Gasoline Fumes]

I went to a few dealerships and took pictures of the deflectors on different vehicles. Only one salesman was even remotely interested in what I was doing, the rest lost interest when they realized I wasn't buying. These are all on the front tires. No Prius or Insight was available.

I thought the Ford Focus was really interesting. Three deflectors that wrap around the tire!



Full width dam on the Ford Fiesta:


Doubles on the Honda CRZ:


I forget what cars these were, I think Toyotas and/or Subarus:

[Joenavy85]

the third to last one looks good, just big enough to cause a wave off to each side around the tire, just small enough that the air will minimally affect the apparent frontal area

[piers.singer]

Great post, Fumes, gives me food for thought.

It's interesting to note how small the OEM deflectors are compared to some of the DIY jobs on here (if you've acres of coroplast then you might as well use it), maybe the manufacturers are saving material/cost or maybe they don't want the aero parts to impact on the car's styling. I don't know, but I'm beginning to think that it's often the little things that can make a big difference to FE.

[robchalmers]

Wish i could post the ones we're fitted here at Bentley all of the continent series run deflectors and front and back belly pans (mainly to help top speed though )

[Bill in Houston]

Smaller OEM ones might be more efficient, or they might just be more practical. Like the Fiesta's deflector - it is probably in three pieces so that people can hit curbs without damaging it, or so that snow doesn't collect in it, or something like that.

It is definitely encouraging to see that the mfgs go to the troule of putting even small flat ones on - tells me that even if you can't put a large, streamlined one on, whatever you put on will probably help.

Also notable to me on that Fiesta is the giant, smooth front undertray. Very nice.

[lunarhighway]

i think it's fair to say all these dams where sized in the wind tunnel to be as eficient as possible without compromising minimal ground clearance and likely style too.

i read in an old autospeed article on these things that to large would once again cause drag, but that these dams also had an effect on front lift, so it's likely they're designed to strike a balance between these things.

to me it seems most are more aimed at keeping air away from the gap behind the wheel where the suspention is, rather than the tire itself

[Gasoline Fumes]

I can't help posting the FJ Cruiser!

[Piwoslaw]

Good job, GF

So, are front spats useful if the car already has a full width airdam under the front bumper?

[California98Civic]

Thanks for these images. Nice little archive. It's really interesting how often the spats cover only the inside half of the tire. I take it the idea is to avoid lift and to avoid a blast of air shooting out the side of the car like a snowplow in a blizzard. I built mine of a modest size, in imitation of some testing done on a first gen prius that one of you all shared on this site. They're small, but they cover 2/3 of the tire and they block the inside bottom of the wheel well (as the modded Prius had).

[lunarhighway]

i think they could be.. the 2011 opel astra has this combination, i can't find a drag figure for it so it may not be all that great, but considdering ground clearance and approach angles airdams can never go as low as you'd want them, but being closer to the tires wheel dams can.



the combination i think is best and what a lot of low Cd cars run is a central undertray, lower side airdams in front of the wheels and suspention and small wheel dams as pitures